The present invention is concerned with the efficient obtainment of additional useful service from carton checking stop paddle gate structures of automatic carton closing machines of the types shown in U.S. Pat. Nos. 3,382,645 of May 14, 1968 and 3,496,697 of Feb. 24, 1970. As background information in this automatic carton closing machine art, U.S. Pat. No. 3,382,645 teaches the use of an electrical control system of a plurality of solenoid valves which are cooperatively associated to dictate pneumatic operative raising and lowering of a carton stop paddle, and U.S. Pat No. 3,496,697 teaches the use thereof in a machine equipped with an Up/Down or lifting and lowering carriage which in its upper position serves as an initial conveyor section leading to the swung up stop paddle and ultimately, after the latter is swung down to free the carton for further advance, transfers the carton to oblique rollers on the opposed inner sides of the longitudinally-extending clamping rails converted at that time to guide rails. The present inventive improvement is concerned with the carton stop paddle, its mount, and the operative mechanism which manipulates it with additional and desired service thereof made possible by the latter.
The swinging operation of the stop paddle is designed to perform three functions. The first function (1) is to swing up, preferably slowly, and stand upright upon the raised lift and lowering carriage to provide a closed gate in the forward path of a loaded carton that has just entered the machine and is advancing on this carriage with its top open and with its bottom flaps folded upward into a temporary bottom closing stack. The second function (2) is to swing down, preferably fast, out of the way of this carton, i.e., release it, as an oncoming cross flight of the chain conveyor which was started up after the leading upstanding top end flap was folded back down by the lowered head so that the trailing top end flap can be folded forwardly down and the upstanding top side flaps can then be plowed down thereover as this carton is conveyed forward. This second function includes simultaneously transferring the closed carton, while being urged forward, from the lowering carriage to oblique support rollers on the side guide rails so that the upfolded bottom side flaps will droop obliquely down to allow the upfolded bottom end flaps to travel over an adhesive applying head for applying adhesive on them during further carton advance, with the help of a sloped manifold plate fixed to this adhesive head to guide the leading upfolded bottom end flap up thereover to above this head. The third function (3) is to raise this stop paddle, preferably quickly, back up to an intermediate and forwardly oblique position for causing its top surface to be directed slightly above the oblique top surface of the sloped manifold plate, so that the leading free end of the upfolded trailing bottom end flap, which may now be drooping from carton load thereon, will be guided up these successive upwardly sloped surfaces also for assuring the riding thereof over the adhesive applying head.
At the end of a cycle of processing a loaded carton through the machine to fold and anchor its top and bottom flaps the entrance gate is retracted to allow the entry of the next loaded carton upon the lifted Up/Down carriage for travel toward the locality of the stop paddle. This is permitted by the fact that the pair of longitudinally elongated and transversely opposed clamping and guiding rails have been spread widely apart at the end of the preceding cycle of operation on the preceding carton for entry therebetween of this next oncoming carton. As these transversely opposed clamping and guiding side rails were spread widely apart at the end of the preceding cycle of action on the last carton processed therethrough a control manipulated at that time, e.g., a trigger tripped by the exiting carton, may cause manipulation of means to dictate relatively slow rise of the stop paddle into the path of this next oncoming carton. Preferably, this action of the stop paddle is effected by pneumatically driven motive means, as is the outward spreading and inward approaching of the clamping rails by a separate such pneumatic motive means. A plurality of solenoid valves in a pressurized gaseous medium system, such as three thereof (herein referred to for identification as SV1, SV3, and SV17), may be employed for this purpose.
Prior to the commencement of a cycle of operation of such equipment solenoid valve SV17 in de-energized condition supplies through a passage in its solenoid movable spool or core relatively highly pressurized air to and through a passage in the solenoid movable spool or core of solenoid valve SV3 for feed to one section of a dual piston pneumatic cylinder motor which applies retracting force to the piston means thereof. The exiting carton activated means causes energization of the solenoid valve SV3 so as to substitute another passage through its spool for the preceding one pneumatically to separate the side rails widely and to direct pressurized air to behind the main piston head of a pneumatic cylinder which lifts the stop paddle to its upright carton-stopping position. This raising action of the stop paddle preferably is at a relatively slow rate as is determined by adjustment of the rate of bleed off of pressurized air through escape valve means, and takes place partially as the side rails separating pneumatic motor or cylinder drives these rails apart by relatively high pressure. The final increment of slow raise of the stop paddle is effected just prior to arrival of the oncoming carton thereagainst and while the side rails are now moving inward toward opposite sides of the carton as it is stopped by the raised paddle for clamping the carton thereat at relatively high pressure, all as dictated by energization of solenoid valve SV1 as SV3 remains energized.
Following the completion of the uses of the closed gate function of the raised stop paddle and the cooperative carton clamping action of the side rails at the flap folding station beneath the elevating head the clamping action at relatively high pressure is reduced to a low pressure of only a few psi so as to convert the contacts of the carton sides by the rails to a guidance action which permits the chain conveyor to advance the carton therebetween. This condition is attained by de-energizing the solenoids SV1 and SV3 with maintenance of the de-energization of SV17 so that high pressure air is fed successively through the latter, an alternate passage in SV3 and other equipment to in front of the main piston head reversely to retract the latter for fast drop of the stop paddle to its lowest substantially flat position. Means are provided which dumps the retracting pressurized air in front of this main piston as the latter is fully retracted so that the stop paddle may rise rapidly to its intermediate position. This rapid dropping of the stop paddle and the dumping of the air from in front of this main piston occur at the time when the low pressure air is biasing the side rails lightly against the advancing carton sides as guides.
The use of this stop paddle to serve as a bottom end flaps guide ramp for assuring that they will ride up and over the adhesive applying head as the carton is advanced from the stop station beneath the top flaps folding head requires the somewhat rapid rise of this paddle to its intermediate oblique or forward sloping position. This rapid rise of the stop paddle is attained by maintaining the deenergization of SV1 and SV3 and now energizing SV17. The pneumatic cylinder motor has, in addition to its main head chamber in which its main piston head reciprocates, an auxiliary chamber in which a secondary piston head reciprocates with shorter stroke to effect the secondary upward swing of the stop paddle that is appreciably shorter than that of the full stroke which attains the upward swing to the upright stop-carton position. This secondary upward swing of the paddle is to its "intermediate position" which provides the upwardly and forwardly sloping ramp that guides the end flaps up over the adhesive applying head.
It is an object of the present invention to provide effective means for obtaining the above and related advantages in economical and reliable manners.
Another object of the invention is to provide simple and reliable means that will cause existing structures of the prior art economically to perform additionally desirable functions without requiring costly and complicated supplemental structures, such as means whereby the stop paddle not only performs its original intended stop-carton function, but will also convert to a forwardly and upwardly sloping effective ramp for guiding upfolded carton bottom end flaps upward over an adhesive applying head.